This present invention relates to navigation systems and more particularly to a navigation system with a vehicle location display for showing a vehicle""s current location and the location of the desired route.
Navigation systems generally provide a recommended route from a starting point to a desired location. Generally, the starting point and desired location are selected from a large database of roads stored in a mass media storage, such as a CD ROM, which includes the roads in the area to be traveled by the user. The navigation system can be located in a personal computer or it can be installed in a vehicle. If the navigation system is installed in a vehicle, the starting point is typically the current position of the vehicle, which can be entered into the navigation system by an associated position determining system that usually includes a Global Positioning System (GPS) receiver.
The navigation system determines a route from the starting point to the destination utilizing an algorithm well-known to those in the art and currently in use in many navigation systems. Usually there are many potential routes between the selected starting point and the desired destination. Typical navigation systems select a recommended route based upon certain predetermined criteria including the length of the route and the estimated time of travel on the route. Depending upon the predetermined algorithm of the navigation system, the navigation system will recommend the route with the shortest total length, the lowest total time, or some weighted average of length and time.
The recommended route is then displayed to the user as a map showing the starting point, desired destination and highlighting the recommended route. Preferably, if the navigation system is installed in a vehicle, the navigation system displays the current location of the vehicle and provides turn-by-turn instructions to the driver, guiding the driver to the selected destination along the recommended route.
The typical navigation system provides the current vehicle location to the user by displaying either a textual guidance mode screen having a set of instructions and the current location or a guidance mode map showing the starting point, desired destination, current location and highlighting the recommended route.
One disadvantage with current displays is that the present location of the vehicle and the starting point of the recommended route may not be able to be seen on the display screen at the same time. This can occur in a situation where the vehicle is moving while the route is being determined and the current position of the vehicle and the nearest point on the recommended route can no longer be in the same screen due to the current display scale. This makes it difficult for the user to proceed to the starting point of the recommended route. Some map displays permit the user to select a viewing scale to aid the driver in showing his current position in relation to the starting point of the recommended route, but this requires further input from the user while the user is en route. Accordingly, it is desirable to provide a vehicle location display that automatically scales the display to show a vehicle""s current location and the starting point of a recommended route on the same screen.
In general terms, this invention provides a vehicle location display for a navigation system. The vehicle location display displays the current vehicle location on a display device of a navigation system in a graphical display mode. In the graphical display mode, the display displays a map having the current location of the vehicle. The navigation system includes a database of roads and a system for determining the current position of a vehicle in relation to the database. A user can select a desired destination in the database by using an input device connected to the navigation system. The navigation system also includes a system for determining a route to the destination. A display displays the route and the vehicle""s current position by automatically scaling the display to include the route and the current position.
These and other features and advantages of the present invention will become more apparent to those skilled in the art from the following detailed description of the presently preferred embodiment. The drawings that accompany the detailed description can be described as follows.